1. Field of the Invention
This invention relates to an inflatable genitourinary prosthesis and to hypdermic injecting instruments for positioning, injecting and inflating the prosthesis so that increased occlusive pressure may be accurately applied to a patient's urethra for holding the patient continent. The prosthesis includes an expandable anti-migration membrane which may be percutaneously infused with fluid or suspended particulate matter so as to increase localized tissue volume while preventing the possible migration of such fluid or particulate matter.
2. Prior Art
As will be known to those skilled in the art, in cases where the natural sphincter muscles of a patient have been surgically excised, damaged by disease or compromised by physical trauma, an artificial prosthetic sphrincter has often been implanted so that occlusive pressure may be applied to the urethra to restore continence. Artificial sphincters are well-known and specific examples thereof will not be listed. However, the implantation of an artificial sphincter commonly requires a major surgical procedure which necessitates the hospitalization of the patient. Such a procedure is relatively complex and expensive, and usually requires six to eight weeks or more of recovery time. In most cases, the patient also faces approximately two months delay before activation of the prosthesis to even ascertain whether the surgery has been successful (i.e. the patient is continent). More particularly, because of the swollen and aggravated condition of edema of the urethral tissues during, and for a period subsequent to surgery, the physician cannot precisely match the occlusive pressure to the patient's urethra. Therefore, the physician must estimate the required minimal occlusive pressure needed to achieve continence in that particular patient. As a consequence of such estimate, sphincteric mechanisms are often improperly selected or fitted, so that the occlusive pressures generated by such mechanisms are either insufficient to successfully achieve continence or excessive to the point of causing ischemia and subsequent erosion of urethral tissue. Excessive circumferential occlusive forces will eventually effect blood flow to the urethra and thereby cause ischemia and subsequent erosion. Also, if the implant surgery should prove to be unsuccessful (i.e. the maximum occlusive pressure to be generated by the sphincter is insufficient to hold the patient continent or the sphincter malfunctions mechanically), then additional surgery becomes necessary to provide sphincter adjustment, repair or explant.
Reference is now made to "Migration And Granulomatous Reaction After Periurethral Injection Of Polytef (Teflon)" by Anthony A. Malizia, Jr. et al, Journal of the A.M.A., June 22/29, 1984, Vol. 251, No. 24, pp. 3277-3281. It has been demonstrated in humans that urinary incontinence may be successfully treated by non-surgical means with periurethral injection of polytef paste to increase localized tissue volume and thereby increase external occlusive pressure to the urethra for causing a partial obstruction and, thus, continence. However, this article reveals wide spread migration of polytef particles from the injection site. In addition, such paste was found to induce tissue reaction with TEFLON granulomas. Because of the possible toxicity of TEFLON-based paste, concern for patient safety has also been expressed. Hence, an otherwise sound, non-surgical procedure has now experienced reduced application.